Public Transportation from SeaTac Airport:  Staffed Ground Transportation Information Booths are both on level 3 of the Parking Garage, and in the Main Terminal's Baggage Claim, opposite Carousel 12: 
The Shuttle Express is the only on demand door-to-door shuttle service at SeaTac, covering Seattle, Tacoma, Everett & the Eastside; it also provides limos, buses & charter services.
The shuttle for Kenmore Air picks up outside Door 00 on the baggage claim level.
The QuickShuttle operates scheduled bus service to Vancouver, Canada, making stops at downtown Seattle, Bellingham Airport and drop-offs inside the Canadian-US border.

Available Transportation Outside of the Baggage Claim Level:
Near door 00: scheduled Airporters, Cruise Line buses, & Charter buses. 
Near Door 02 are public transit buses 'Sound Transit 560 & 574;
Near Door 02 & 24 are rental car shuttles to Rental Car Center
Across from Arrivals S Drive (accessed from lower baggage level of passenger terminal) is the bus stop island for Courtesy vehicles &  Downtown Airporter. The Ground Transport Info Booth is reached by escalator.

    The Link Light Rail* to the City
is on level 4 of the Parking Garage - departing  from the new SeaTac/Airport Station (accessible from the Main Terminal's Skybridge 6 on the Ticketing Level, connecting there to a pedestrian covered walkway - also used for Public Bus station (at opposite side, at Skybridge 6, it leads to level 4 of the Parking Garage). Trains run every 7.5 minutes during rush hours and every 15 minutes thereafter, Mon-Sat 5am-1am & Sun 6am-midnight.  Wheelchair service is available. Signs will guide you.
    The King County Metro bus station on International Blvd. /State Hwy 99 can be reached from the Main Terminal's Skybridge 6 on the Ticketing Level, connecting there to a pedestrian covered walkway  leading to  Sound Transit Link Light Rail Station; exit there to International Blvd. The Bus stop has timetables - or pick up one at ground transportation info booth near door 16. For more information open: tripplanner.kingcounty.gov
    Sound Transit express routes 560 & 574 make pickups/dropoffs at main terminal bus stop on lower drive.  For more information open: www.soundtransit.org/

* NOTE:  By late 2016, the 1.6 mile elevated guideway & station of the Link Light Rail Extension project  - including  its University Link , is scheduled to be completed.

Google Plus One